On 2020/5/20 13:41, Richard Henderson wrote:
On 5/19/20 7:37 PM, LIU Zhiwei wrote:
On 2020/5/12 1:40, Richard Henderson wrote:
On 4/30/20 12:21 AM, LIU Zhiwei wrote:
+ # sequence of li rd, 0x1234567887654321
+ #
+ # 0: 002471b7 lui rd,0x247
+ # 4: 8ad1819b addiw rd,rd,-1875
+ # 8: 00c19193 slli rd,rd,0xc
+ # c: f1118193 addi rd,rd,-239 # 0x246f11
+ # 10: 00d19193 slli rd,rd,0xd
+ # 14: d9518193 addi rd,rd,-619
+ # 18: 00e19193 slli rd,rd,0xe
+ # 1c: 32118193 addi rd,rd,801
You don't really need to use addiw. Removing that special case would really
simplify this.
I think I don't get it. Do you mean that the immediate will not be 64 bit?
Well, mostly the immediate will be small, actually. But the interface must
support 64-bit immediates.
I'm saying that for this computation,
lui
addi
slli
addi
...
is the same. You don't *have* to use addiw.
I see addiw is not good, as it is a RV64 only instruction. I think addi
is right and better.
But I'm afraid I don't get
"Removing that special case would really
simplify this."
Do you mean I need not the decode_li function if I use addi instead of
addiw?
Zhiwei
r~
